-They appear some amount of milliseconds after you die. I think it's either a full second or half a second after you, but in any case, your tank could have still moved a bit after you died if you were reversing fast enough.

-Tracers automatically focus in on the center of mass on your tank anyways, so if you got shot from the front, it'll look like it went through the drive wheel, which is what it did.

Tracers are a very unreliable way to see how you died at the end. I've had some tracers drop from heaven because it got messed up. That T30 probably penned your lower plate or finished you off with HE and just needed to contact your tank somewhere.